Liquid crystal display device and method for manufacturing the same

ABSTRACT

A liquid crystal display device comprises: first and second transparent substrates; a liquid crystal that is enclosed between the first and second transparent substrates; a first color filter that is formed on either the first or second transparent substrate; a light reflective layer that has a plurality of openings and that is formed on the second transparent substrate toward the liquid crystal; and a second color filter that is formed on the second transparent substrate on the side opposite to the liquid crystal. The second color filter is fabricated by forming a layer of a color photosensitive material such as a photosensitive emulsion and illuminating and coloring this layer by light transmitting through the first color filter using the reflective layer as an exposure mask. As a result, a second color filter, that has a color dot pattern the same as that of the first color filter, is formed by one exposure and developing process.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority of Japanese Patent Application No.2002-377005, filed on Dec. 26, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a transflective liquid crystal displaydevice that can be used in both transmissive and reflective modes and amethod for manufacturing the same.

2. Prior Art

Transflective liquid crystal display devices, which operate in areflective mode utilizing ambient light in bright places and operate ina transmissive mode utilizing backlight in dark places, are broadlyused, in particular, as display devices in portable electronicequipment. For example, Japanese Unexamined Patent Publication No.H10-282488 entitled “Liquid crystal display device” proposes a liquidcrystal display device in which holes for transmitting light areprovided on a reflective layer of a reflective liquid crystal displaydevice and, at the same time, a backlight device is provided behind thereflective layer. When this device is used in the reflective mode, animage is displayed by the ambient light reflected by the reflectivelayer disposed behind a liquid crystal layer and, when this device isused in the transmissive mode, the image is displayed by guiding thelight from the backlight device to the liquid crystal cell through theholes provided on the reflective layer.

However, the device disclosed in Japanese Unexamined Patent PublicationNo. H10-282488 has a problem in that, in a color display mode, colorreproducibility is not optimized in both the reflective mode and thetransmissive mode. The reason of this problem is as follows. When thedevice is used in the reflective mode, the ambient light passes throughthe liquid crystal layer and a color filter and is reflected by thereflective layer disposed on the backside of the color filter and, then,passes through the color filter and the liquid crystal cell again and,then, exits from the cell and is observed by a user. Therefore, as theincident light passes through the color filter twice before exiting fromthe cell, the transmittance of the light and, thus, the brightness ofthe display is reduced by the color filter. As the light passes throughthe color filter twice, the color saturation of the light is increased.In contrast to this, when the device is used in the transmissive mode,as the light that is originated from the backlight device disposedbehind the cell passes through the holes disposed on the reflectivelayer and, then, passes through the color filter and liquid crystal celland exits from the cell, the light passes through the color filter onlyonce. Therefore, the brightness of the display is not reduced but thecolor saturation is reduced. As described above, as the colorreproducibility is not optimized in both the transmissive mode and thereflective mode, there is a problem in that, if the optical density ofthe color filter is optimized for either the transmitting mode or thereflective mode, the display in the other mode is not optimized.

In order to solve the above problem of the liquid crystal display deviceshown in Japanese Unexamined Patent Publication No. H10-282488, otherliquid crystal display devices have been proposed in Japanese UnexaminedPatent Publication No. 2000-298271 entitled “Liquid crystal displayelement and method for manufacturing the same”, Japanese UnexaminedPatent Publication No. 2001-33778 entitled “Liquid crystal displaydevice and method for manufacturing the same and electronic equipment”and the like. As these liquid display devices are configured so that thethickness of the color filter differs between the region above areflective layer and the region above openings of the reflective layer,the same color reproducibility can be obtained in both the transmissiveand reflective modes. For example, by making the thickness of the colorfilter above the openings of the reflective layer twice as large as thatof the color filter above the reflective layer, the thickness the lightpasses through in the color filter is same in both the transmissive andreflective modes and, as a result, the same color reproducibility of thedisplay can be obtained in both modes.

However, in the devices described above, in order to provide the colorfilter with different thickness between the region above the reflectivelayer and the region above the openings, the reflective layer must bethicker having a two-layer construction comprised of a resin layer and areflective layer and, further, two layers of the color filter must beformed. In the case of a three-color filter, in order to form the twolayers of the color filter, an exposure and developing process must berepeated six times and, therefore, the manufacturing process becomescomplicated and the production cost of the liquid crystal display deviceitself is increased.

SUMMARY OF THE INVENTION

In view of the above problems, it is an object of the present inventionto provide a transflective liquid crystal display device of a novelconstruction that does not require a complicated manufacturing processand that can obtain an appropriate color reproducibility of a display inboth a reflective mode and a transmissive mode, and a method formanufacturing the transflective liquid crystal display device.

In order to achieve the above object, according to the presentinvention, there is provided a liquid crystal display device,comprising: first and second transparent substrates; a liquid crystalthat is enclosed between said first and second transparent substrates; afirst color filter that is formed on either said first or secondtransparent substrate; a light reflective layer that has a plurality ofopenings and that is formed on said second transparent substrate towardthe liquid crystal; and a second color filter that is formed on saidsecond transparent substrate on the side opposite to said liquidcrystal.

When said device is used in the reflective mode, an incident light thatcomes on this device from above the first transparent substrate passesthrough the first color filter and is reflected by the reflective layer,passes the first color filter again and exits from this device and isobserved by a user. Therefore, the incident light passes the first colorfilter twice. On the other hand, when this device is used in thetransmissive mode, light that is originated from a backlight devicedisposed on the backside of the second transparent substrate passesthrough the second color filter and further passes through the openingsof the reflected plate and the first color filter and, then, exits fromthis device and is observed by the user. Therefore, as the light fromthe backlight passes through the second and first color filters, if thefirst and second color filters have the substantially same opticaldensity, an appropriate color reproducibility of the display can beobtained in both the reflective and transmissive modes.

The liquid crystal display device of the present invention describedabove is manufactured by a method comprising the steps of: forming areflective layer having a plurality of openings and then a first colorfilter on a second transparent substrate sequentially; applying a colorphotosensitive material on a surface of said second transparentsubstrate on the side opposite to that on which said reflective layer isformed; forming a second color filter that has a color dot matrixpattern the same as that of said first color filter by illuminating saidcolor photosensitive material from above said first color filter throughthe openings of said reflective layer; disposing a first transparentsubstrate opposed to the surface of said second transparent substrate onwhich said first color filter is formed; and filling a liquid crystalbetween said first and second transparent substrates.

According to the manufacturing method described above, the second colorfilter mentioned above is formed by exposing and coloring the colorphotosensitive material on the surface of said second transparentsubstrate on the side opposite to said liquid crystal by the lighttransmitting through said first color filter and by using saidreflective layer as an exposure mask. Therefore, in contrast to theprior art wherein the same number of coloring processes as the number ofcolors is needed, the coloring process must be performed only one timefor the second filter and, therefore, the manufacturing process issimplified significantly and the production cost of the device isreduced.

Further, the liquid crystal display device of the present inventiondescribed above is manufactured by a method comprising the steps of:forming a reflective layer having a plurality of openings and then afirst color filter on a second transparent substrate sequentially;disposing a first transparent substrate through a sealing memberopposite to and above a surface of said second transparent substrate onwhich said reflective layer and first color filter are formed; applyinga color photosensitive material on a surface of said second transparentsubstrate on the side opposite to that on which said first color filteris formed; forming a second color filter by illuminating said colorphotosensitive material from above said first transparent substratethrough said first color filter, said openings being provided on saidreflective layer and said second transparent substrate and coloring thematerial; and filling a liquid crystal between said first and secondtransparent substrates.

According to the manufacturing method described above, as the processfor forming the second color filter is performed after the liquidcrystal cell is constituted by the first and second transparentsubstrates, there is an effect in that, when the second color filter isformed, the contamination of the surfaces of the liquid crystal cell andthe damage of the substrates due to handling of the substrates can beprevented and, therefore, the liquid crystal cell can be handled easily.

Still further, the liquid crystal display device described above ismanufactured by a method comprising the steps of: forming a reflectivelayer having a plurality of openings and then a first color filter on asecond transparent substrate sequentially; disposing a first transparentsubstrate through a sealing member opposite to and above a surface ofsaid second transparent substrate on which said reflective layer andfirst color filter are formed; filling a liquid crystal between saidfirst and second transparent substrates; applying a color photosensitivematerial on a surface of said second transparent substrate on the sideopposite to said liquid crystal; and forming a second color filter byilluminating said color photosensitive material from above said firsttransparent substrate through said liquid crystal, said first colorfilter, said openings provided on said reflective layer and said secondtransparent substrate, and coloring the material.

According to the manufacturing method described above, after the liquidcrystal cell is constituted by the first and second transparent cell andthe liquid crystal is filled into the cell, the process for forming thesecond color filter is performed using the photosensitive emulsion. As aresult, dust or other contaminants can be prevented from being mixedinto the liquid crystal at the time of exposure and developing of thephotosensitive emulsion and, therefore, a liquid crystal display devicehaving high reliability can be obtained.

In this connection, said first color filter is formed by either aphotolithography, printing, electrodeposition or inkjet method. Further,said color photosensitive material is a photosensitive emulsion and thestep of forming said second color filter comprises the step ofdeveloping said photosensitive emulsion that has been exposed. Thisphotosensitive emulsion is, for example, a silver chloride emulsion. Asthe silver chloride emulsion is sensitive to ultraviolet (UV) light, itis preferable that the polarizer has a UV screening function.

Further, the color filters may have three colors of red, green and blueor three colors of cyan, magenta and yellow. Further, it may have othercombinations of colors. The reflective layer can be formed by a film ofaluminum or silver or alloys including these metals and is provided withopenings at positions corresponding to regions of each color of thecolor filters.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows a cross section of a liquid crystal displaydevice according to a first embodiment of the present invention;

FIGS. 2(a)-2(f) show steps of a manufacturing process of the deviceshown in FIG. 1;

FIGS. 3(a)-3(f) show steps of a manufacturing process of a first colorfilter;

FIG. 4 shows one step of a manufacturing process of the device shown inFIG. 1;

FIGS. 5(a)-5(c) show steps of a manufacturing process for a plurality ofliquid crystal display devices simultaneously according to amanufacturing method for liquid crystal display device; and

FIG. 6 schematically shows a cross section of a liquid crystal displaydevice according to another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of a transflective liquidcrystal display device according to a first embodiment of the presentinvention. The shown embodiment is an STN liquid crystal display device,wherein transparent substrates 1 and 2, such as glass sheets, constitutea top substrate and a bottom substrate of a liquid crystal cell,respectively. Then, signal electrodes 3 are formed on a surface of thetop substrate 1 facing a liquid crystal layer and a common electrode 4is formed on a bottom substrate 2. Typically, these are comprised oftransparent electrodes. In this connection, a reflective layer and afirst color filter described below are disposed between the bottomsubstrate 2 and the common electrode 4. Then, alignment layers 5 and 6and a liquid crystal layer 7 are shown. The top substrate 1 is providedwith a retardation film 8 and a polarizer 9 on the side opposite to theliquid crystal layer 7 and the bottom substrate 2 is also provided witha retardation film 10 and a polarizer 11 similarly. Then, a backlightdevice 12 is shown. The bottom substrate 2 is provided with thereflective layer 13 that is a deposited film of aluminum or the like andthe first color filter 15 on the side toward the liquid crystal layer 7.The color filter 15 is constituted by a plurality of repetitions ofthree color dots of R, G, B. The reflective layer 13 has openings(holes) 16 at positions corresponding to central positions of each dotof the color filter 15. Further, a planarizing layer 17 is formed on thefirst color filter 15 for planarizing a top surface of the color filter15.

In this device, the bottom substrate 2 is further provided with a secondcolor filter 18 on the side facing the backlight device. This secondcolor filter 18 is formed when a photosensitive emulsion layer appliedon the bottom substrate 2 is exposed and developed by light applied fromthe direction of the first color filter 15 by using the reflective layer13, through which the openings 16 are formed, as a mask, as describedlater.

When the first color filter 15 described above is formed, the opticaldensity of the color filter is optimized solely with respect to thecolor filter 15 so as to obtain proper color reproducibility whendisplaying in a reflective mode. The optical density of the second colorfilter 18 is optimized to be substantially similar to that of the firstcolor filter 15. As a consequence, the transmittance of the lightpassing through the second color filter 18 and the first color filter 15is equal to that of the light that is reflected by the first colorfilter 18 and returns toward the user and, therefore, an appropriatecolor reproducibility can be obtained in both transmissive andreflective modes.

Here, the openings 16 are not necessarily formed at the centralpositions of the respective dots (each of which corresponds to one pixelof the liquid crystal display device) on the reflective layer 13 and theopenings 16 may be offset from the central positions. Further, each dotdoes not necessarily correspond to one opening and a plurality ofopenings may be formed in each dot. The ratio of the total area of theopening(s) in one dot to the area other than the opening(s), or theopening/dot (pixel) ratio is often about 30-60%.

Further, an insulating layer may be provided in at least one of theregions between the top substrate 1 and the alignment layer 5 andbetween the bottom substrate 2 and the alignment layer 6 to preventshort circuits between the transparent electrodes on the top substrate 1and the transparent electrode on the bottom substrate 2 due to dust. Theconfiguration of the retardation films 8 and 10, the polarizer 9 and 11and the material of the liquid crystal layer 7 may be those that aretypically used for STN liquid crystal display devices, for example, thespecific description of which is omitted here.

FIGS. 2(a)-2(f) are diagrams showing a process for forming the first andsecond color filters 15 and 18, described above, on the bottom substrate2 according to a method of the present invention. First, on a topsurface of the bottom substrate 2 shown in FIG. 2(a), the reflectivelayer 13 is formed as shown in FIG. 2(b). Next, as shown in FIG. 2(c), aplurality of openings 16 are formed on the reflective layer 13. Theopenings 16 are disposed at positions corresponding to respectiveregions of each color of the second color filter to be formed later.Then, as shown in FIG. 2(d), the first color filter 15 is formed on thereflective layer 13. Though the color filter 15 may be formed by anymanufacturing process, an example will be shown in FIG. 3.

The example of a method for manufacturing the first color filter 15 willbe described with reference to FIGS. 3(a)-3(f). Here, in FIGS.3(a)-3(f), for simplicity of description, the reference numeral 2′indicates the bottom substrate in the step shown in FIG. 2(d) and,therefore, the reflective layer 13 is formed on the substrate 2′, thoughnot shown, and the openings 16 are formed on the reflective layer 13.First, on the substrate 2′ shown in FIG. 3(a), a layer 150 of a colorfilter raw material, which will be developed and patterned later, isformed as shown in FIG. 3(b). This layer 150 contains a pigment or a dyehaving a color such as red. Next, as shown in FIG. 3(c), the layer 150is covered by an exposure mask 152 and, then, is exposed to light sothat it is colorized and patterned. Then, the exposure mask 152 isremoved as shown in FIG. 3(d) and, then, unnecessary portions of thelayer 150 are removed by developing or other processes so as to form onecolor portion (for example, a red portion) as shown in FIG. 3(e). Then,a portion of another color of the color filter is formed by forming abase layer containing a pigment or a dye of the another color on thebottom substrate 2′ and performing the exposure and developing in amanner similar to the above process. By repeating this process furtheronce again, a color filter 15, on which a plurality of dots of red (R),green (G) and blue (B) colors are formed, is formed as shown in FIG.3(f).

FIG. 2(d) shows the first color filter 15 formed on the bottom substrate2 as described above. Here, as exemplary structural values of the colorfilter 15 and the reflective layer 13, for example, the size of thepixel is 180 μm×60 μm and the diameter of each opening 16 is about 40μm. The thickness of the first color filter 15 is about 0.8 μm. Thereflective layer 13 is formed of aluminum by the sputtering method andits thickness is about 0.15 μm, but the thickness may be increased toabout 0.8 μm by forming the reflective layer of other materials ordisposing a resin film under the reflective layer. Further, as discussedabove, the ratio of the total area A of the opening(s) in one dot to thearea B other than the opening(s), or the opening (A)/dot (pixel) (A+B)ratio is often in the range of 30-60%.

Next, a process for forming the second color filter 18 will bedescribed. As shown in FIG. 2(e), a photosensitive emulsion layer 18′ isformed by turning the bottom substrate 2 upside down and applying asilver-halide emulsion to its upper surface by a spinner, a squeegee ora printing method. Then, as shown in FIG. 2(f), the silver-halideemulsion layer 18′ is exposed by using a white light source, wherein thelight from the white light source is transmitted through the first colorfilter 15 and passes through the openings 16 of the reflective layer 13to impinge on the photosensitive emulsion layer 18′ and expose it. Then,by developing the photosensitive emulsion layer, the regionscorresponding to the openings 16 are colored according to the colorpattern of the first color filter so that the photosensitive emulsionlayer acts as the second color filter. Here, light sources other than awhite light source may be used for the exposure. For example, separatelight sources may be provided for each of red, green, blue colors andlit simultaneously or a three wavelength light source tube may be used.

As described above, by using the reflective layer 13 as the lightshielding mask (exposure mask) and exposing the photosensitive emulsionlayer 18′ to the light passing through the first color filter 15, thesecond color filter 18 having a three-color pattern is formed by oneexposure and developing process. Therefore, the manufacturing process ofthe second color filter 18 is simplified significantly in comparisonwith that of the first color filter. In this connection, some portionsof the photosensitive emulsion 18′ below the reflective layer 13existing between the adjacent openings 16 may not be exposed anddeveloped but, even if there are such portions that are not exposedadequately, the appearance and display quality of the liquid crystaldisplay device is not degraded because such portions are covered by thereflective layer 13 from the viewpoint of the user.

After the bottom substrate 2 having the two layers of the color filtersshown in FIG. 2(f) has been formed as described above, the planarizinglayer 17 is formed on the color filter 15 and, then, the commonelectrode and the alignment layer 6 are formed in a typical manner. Thebottom substrate 2 in this state is opposed to the top substrate 1, onwhich the signal electrodes and the alignment layer are formedseparately, so that each electrode forms the respective pixels and,further, the both substrates are coupled together through a frame-likesealing member to constitute the liquid crystal cell. Next, after aliquid crystal is filled into the cell and the retardation films, thepolarizers and the backlight device are provided appropriately, theliquid crystal display device of the construction shown in FIG. 1 can beobtained.

FIG. 4 is a diagram for describing an alternative manufacturing methodof the second color filter 18 of FIG. 2. In this manufacturing method,the bottom substrate 2, on which the reflective layer having holes andthe first color filter 15 have been formed and the electrodes and thealignment layer have been provided appropriately, is coupled with thetop substrate 1, on which the electrodes and the alignment layer areprovided, to constitute the liquid crystal panel. After or before theliquid crystal is filled into the liquid crystal panel, the second colorfilter 18 is formed on the back of the bottom substrate 2. Morespecifically, the photosensitive emulsion layer 18′ is formed on theback of the bottom substrate 2 and, then, light is allowed to impinge onthe panel from the side of the top substrate 1 to expose thephotosensitive emulsion layer 18′ through the first color filter 15 andthe openings 16. As a result, the photosensitive emulsion layer 18′ isexposed to have a color pattern identical to that of the first colorfilter 15 and, thus, the second color filter 18 is formed. By providingthe retardation films, the polarizers and the backlight device to thesecond color filter 18 that has been formed as described above, theliquid crystal display device shown in FIG. 1 is completed.

According to the manufacturing method of the liquid crystal displaydevice as shown in FIG. 4, the operation to form the second color filter18 can be performed after the top substrate 1 and the bottom substrate 2are coupled together. Therefore, in contrast to the embodiment shown inFIG. 2, the substrate 2 can be handled easily when the second colorfilter is formed. Further, if the process of application, exposure,developing and the like of the photosensitive emulsion is performedafter the liquid crystal is filled into the cell, as it is possible tominimize the possibility that dust or other contaminants are mixed intothe liquid crystal cell while the second color filter is manufactured,the degradation of image quality due to the dust can be prevented, theprobability of the short circuit between electrodes can be lowered evenif the insulating layer is not provided and, therefore, the reliabilityof the liquid crystal display device can be improved.

FIGS. 5(a)-5(c) are diagrams showing an alternative manufacturing methodof the liquid crystal display device of the present invention shown inFIG. 4. This manufacturing method is characterized in that the secondcolor filter is formed simultaneously for a plurality of liquid crystalcells without contaminating the inside of the liquid crystal cell beforefilling the liquid crystal. Hereinafter, with reference to FIGS.5(a)-5(c), this embodiment will be described.

FIG. 5(a) shows a plurality of cells, each of which corresponds to oneliquid crystal display device, formed on a large substrate. In FIG.5(a), two large substrates corresponding to the top substrate 1 and thebottom substrate 2 are coupled together through a first sealing member110 and second sealing members 120 to form a large-sized cell 101. Inthis state, the liquid crystal is not filled into each cell 200 enclosedby the second sealing members 120. These sealing members provide a dualseal and, in each of the cells 200, the second sealing member 120 with afilling hole 125 is disposed so as to form a cell space 130. Theplurality of cells 200 are encircled by the first sealing member 110,wherein the first sealing member 110 is provided with a circulation pathconnecting the inside and outside of the substrates so that air iscirculated therebetween. In order to form this circulation path, twoopenings 121 are provided on the outside and inside of the first sealingmember 110. The first sealing member 110 must be configured to have aregion where portions of the first sealing member 110 itself aredisposed in parallel. Here, functions of the openings 121 and the firstsealing member 110 the portions of which are disposed in parallel willbe described. When the large plate-like top substrate and the bottomsubstrate are coupled together by thermocompression process, with aspacing provided by the first sealing member 110 and the second sealingmembers 120, so as to form the large-sized cell 101, if the spacebetween the top and bottom substrates is sealed completely, the air atthe central part (inside) of the large-sized cell substrate 101 cannotescape to the outside and, therefore, the substrate 101 will bedestroyed by the expansion of the internal air due to the heat from thethermocompression process. The openings 121 are provided to prevent thisproblem. On the other hand, the sealing sections 122 and 124, that arethe portions of the first sealing member 110 disposed in parallel, areprovided to prevent liquids, which are used for cleaning or wetdeveloping in the process after the two substrates are coupled, fromentering into the cells 200.

FIG. 5(b) shows a strip-like substrate into which said large plate-likecell 101 is cut along lateral cutting lines X (X1, X2, X3, X4). In thisstrip-like substrate, as a plurality of cells are arranged in a lateraldirection and the filling holes 125 of all the cells are opened in onedirection, the liquid crystal can be filled into all the cells at onetime by using a vacuum filling method. FIG. 5(c) shows one liquidcrystal cell 200 into which said strip-like substrate is cut alongvertical cutting lines Y (Y1, Y2, Y3, Y4).

Hereinafter, steps of the manufacturing process shown in FIGS. 5(a)-5(c)will be described. In the state shown in FIG. 5(a), in each cell 200,the processes shown in FIGS. 2(a)-2(d) have been completed and, further,the electrodes and the alignment layers have been disposed on the topand bottom substrates and the top and bottom substrates are coupledtogether through the sealing members. Then, though not shown, aphotosensitive emulsion layer is applied on the back of the large-sizedsubstrate 101 and is exposed according to the exposure method shown inFIG. 4. Here, it is to be noted that the liquid crystal is not yetfilled into the cell spaces 130. Then, the wet developing process of thelarge plate-like substrate 101 is performed. At this time, the firstsealing member 110, which is made of a sealing material the same as thatof the second sealing members 120 and is provided in advance,effectively prevents a developer from entering into the spaces 130through the filling holes 125 of each cell 200. The first sealing member110 may have any shape to prevent the developer from entering. In FIG.5(a), the first sealing member is configured so that it makes 1+¼ turnsaround the large substrate. It may alternatively be configured so thatit makes 1+ 2/4, 1+¾ or 2 turns.

In the processes described above, the second color filter is formed onall the cells 200 in the large-sized substrate 101 at a time by onceforming, exposing and developing the photosensitive emulsion layer.Then, after the developing process, the substrate 101, on which thesecond color filter 18 (see FIG. 1) is formed, is cut along the lateralcutting lines X1-X4. At this time, the filling holes 125 are opened onthe cutting planes of the cutting lines X2, X3 and X4. The strip-likesubstrate shown in FIG. 5(b) can be obtained by this cutting operation.In this state, a plurality of filling holes 125 of a plurality of cellsare made to contact with the liquid crystal material and the liquidcrystal is filled into the spaces 130 by controlling the air pressure inthe spaces. After the liquid crystal is filled, the filling holes aresealed by sealing members made of a resin material. Then, the strip-likecells are cut along the cutting lines Y1-Y4 shown in FIG. 5(b) into theliquid crystal cell 200 shown in FIG. 5(c). The retardation films, thepolarizers and the backlight device are attached to the cell 200appropriately to obtain the transflective liquid crystal display device.

FIG. 6 shows a construction of a liquid crystal display device accordingto another embodiment of the present invention. In contrast to thedevice shown in FIG. 1, this device is characterized in that the firstcolor filter 15′ is disposed on the top substrate 1 toward the liquidcrystal. Here, the surface of the color filter 15′ is planarized by theplanarizing layer 17′. In this device, the reflective layer 13 is formedon a surface of the bottom substrate 2 toward the liquid crystal, thephotosensitive emulsion layer that is to be turned into the second colorfilter 18 is formed on another surface of the bottom substrate 2 on theside opposite to the liquid crystal and, then, the second color filter18 is formed by illuminating the photosensitive emulsion layer fromabove the first color filter 15′ using the reflective layer 13 havingthe openings 16 as the exposure mask.

It is to be noted that the retardation film, the polarizer, theplanarizing layer, the backlight device and the like set forth in theabove embodiments are not essential elements to constitute the liquidcrystal display device according to the present invention and these maybe omitted as appropriate depending on the object, design specificationand other conditions of the device. The relationship of the signal andcommon electrodes to the top and bottom substrates may be inverted fromthe shown example. Further, though a passive matrix liquid crystaldisplay device is illustrated in the above embodiments, the presentinvention may also be applied to active matrix (TFT, MIM, TDF) devices,of course. In the case of the TFT liquid crystal display device, oneretardation film may suffice.

Further, though a cross section of one liquid crystal cell is shown inthe above embodiments, a plurality of cells may be formed between a pairof transparent substrates.

As described above in various embodiments, in the device of the presentinvention, an appropriate color reproducibility of the display can beobtained easily in both transmissive and reflective modes. Therefore, atransflective liquid crystal display device having high display qualitycan be obtained. Further, when the photosensitive emulsion is exposed tolight to form the second color filter, as the patterning exposure isperformed by using the reflective layer on which the openings areprovided as the light shielding mask, the process for forming the secondcolor filter can be simplified significantly in comparison with theprior art. In particular, as it is not necessary to change the exposuremask or perform etching at the time of the patterning process, thepatterning can be performed in a short time and working efficiency canbe improved. As a result, a liquid crystal display device having highreliability can be obtained at low cost.

1. A liquid crystal display device, comprising: first and secondtransparent substrates; a liquid crystal that is enclosed between saidfirst and second transparent substrates; a first color filter that isformed on either said first or second transparent substrate; a lightreflective layer that has a plurality of openings and that is formed onsaid second transparent substrate toward the liquid crystal; and asecond color filter that is formed on said second transparent substrateon the side opposite to said liquid crystal, wherein said first colorfilter is formed on said light reflective laver of said secondsubstrate.
 2. A liquid crystal display device according to claim 1,wherein said second color filter is made of a color photosensitivematerial. 3-4. (canceled)
 5. A liquid crystal display device accordingto claim 1, wherein said first color filter is formed of a plurality ofdots comprised of colors of red, green and blue and the center of eachdot of said first color filter agrees with the center of said openingsof said light reflective layer.
 6. A liquid crystal display deviceaccording to claim 2, wherein said color photosensitive materialcomprises a photosensitive emulsion.
 7. A liquid crystal display deviceaccording to claim 1, wherein a backlight device is disposed below asurface of said second transparent substrate and on the side opposite tosaid liquid crystal. 8-16. (canceled)
 17. A liquid crystal displaydevice, comprising: first and second transparent substrates; a liquidcrystal that is enclosed between said first and second transparentsubstrates; a first color filter that is formed on either said first orsecond transparent substrate; a light reflective layer that has aplurality of openings and that is formed on said second transparentsubstrate toward the liquid crystal; and a second color filter that isformed on said second transparent substrate on the side opposite to saidliquid crystal, wherein said first and second color filters havesubstantially equal optical densities.
 18. A liquid crystal displaydevice according to claim 17, wherein said first color filter is formedof a plurality of dots comprised of colors of red, green and blue andthe center of each dot of said first color filter agrees with the centerof said openings of said light reflective layer.
 19. A liquid crystaldisplay device according to claim 17, wherein said second color filteris made of a color photosensitive material.
 20. A liquid crystal displaydevice according to claim 19, wherein said color photosensitive materialcomprises a photosensitive emulsion.
 21. A liquid crystal display deviceaccording to claim 17, wherein a backlight device is disposed below asurface of said second transparent substrate and on the side opposite tosaid liquid crystal.